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General Biology: Phylogeny and Speciation

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이 집합의 용어 (20)

  • What is phylogeny?

    Phylogeny is the evolutionary history of a group of organisms.

  • What is a phylogenetic tree?

    A phylogenetic tree is a graphical representation of a reconstruction of the phylogeny showing relationships among species.

  • What are homologous characters?

    Homologous characters are traits inherited from a common ancestor, such as anatomy, morphology, or DNA sequences.

  • Define root, branches, nodes, and tips in a phylogenetic tree.

    Root: ancestral lineage; Branches: lineages; Nodes: common ancestors (speciation events); Tips: species, populations, or individuals.

  • What is a synapomorphy?

    A synapomorphy is a shared homologous trait that defines a group of organisms.

  • What is homoplasy?

    Homoplasy is a shared trait that is not homologous, often due to convergent evolution or evolutionary reversal.

  • Difference between monophyletic and paraphyletic groups?

    Monophyletic group includes all descendants of a common ancestor; Paraphyletic group includes some but not all descendants.

  • How do phylogenetic trees help understand biodiversity?

    They show relationships among species, reconstruct trait evolution, and indicate when and where speciation events occurred.

  • What is the principle for choosing the best phylogenetic tree?

    The best tree is the one that minimizes the number of evolutionary steps (parsimony).

  • What is allopatric speciation?

    Allopatric speciation occurs when genetic isolation arises due to geographical isolation, such as dispersal or vicariance.

  • Define dispersal and vicariance in speciation.

    Dispersal: organisms colonize a new habitat forming a new population. Vicariance: a physical barrier splits a widespread population into subgroups.

  • What roles do genetic drift and selection play in speciation?

    Genetic drift and selection cause divergence in isolated populations, leading to reproductive isolation.

  • What is sympatric speciation?

    Sympatric speciation is genetic isolation without geographic isolation, often driven by disruptive selection or ecological differences.

  • What is polyploid speciation?

    Polyploid speciation involves changes in chromosome number that cause automatic reproductive isolation.

  • Explain hybrid speciation.

    Hybrid speciation occurs when two species hybridize, producing a reproductively isolated hybrid with unique traits.

  • How does reproductive isolation arise in speciation?

    Reproductive isolation arises from genetic divergence, ecological differences, or chromosomal changes preventing gene flow.

  • What is the Biological Species Concept?

    Species are groups of interbreeding natural populations reproductively isolated from others.

  • What is the Phylogenetic Species Concept?

    Species are the smallest monophyletic groups distinguished by shared derived characters.

  • How can speciation be detected using phylogenomic data?

    By identifying distinct clades with genetic, ecological, and morphological differences supporting species status.

  • What kind of natural selection can cause sympatric speciation?

    Disruptive selection can cause sympatric speciation by favoring extreme phenotypes and reducing gene flow within a population.